interface IMyUser {
  username: string;
  password: string;
}
interface IMyUser {
  age: number;
}

const zhangsan: IMyUser = { username: "张三", password: "123", age: 28 };

type TMyUser = {
  username: string;
  password: string;
};

const lisi: TMyUser & { age: number } = {
  username: "李四",
  password: "123",
  age: 28,
};

type TTest = TMyUser & { age: number };

const wangwu: TTest = { username: "王五", password: "123", age: 28 };
